I have a ten year old son, and he still loves running that Saturn program.
We watched the movie Contact together (the opening scene from that movie is
where I got the idea of zooming in, then away from Saturn) and he enjoyed
that movie and could relate the obfu to it.
In addition to that, I'll often help him write a little program to illustrate
or solve a problem from his Maths homework. Easily solving a tricky problem
with a very simple brute force search program that he was struggling to solve
manually has helped him appreciate the awesome power of computer programming.